[unreadable] [unreadable] We propose to combine magnetic sensor (MN) navigation technology developed for prenatal cardiac intervention (R44HL076961) with our image overlay (IO) solutions to produce an accurate and user- accessible system for rapid, central vascular access (MNIO-VA). Central vascular access is the critical first step in many medical procedures (intravenous infusion of fluids, drugs, and blood; catheter access for intravascular procedures, hemodialysis, or pulsatile mechanical support; to name only a few). However, vascular access is frequently delayed or non-successful due to confounding conditions that include the small size of vessels in infants and children, distortion of vascular landmarks or vascular occlusion following trauma or previous procedures, patient movement during the time required to achieve access, and importantly, the loss of tactile landmarks in the setting of intravascular volume depletion or hypotension. The first needle pass for central vascular access often fails and causes bleeding and/or swelling adjacent to the target vessels which further reduces the likelihood for success. Current practice for acquiring central vascular access includes the use of surface and bony landmarks, tactile sensation, and for some procedures, 2-dimensional ultrasound imaging. However, current ultrasound systems visualize blood flow within vessels but do not provide navigation guidance for vascular access. We developed a robust solution for projecting the trajectory of a stylet and needle onto a 2- dimensional ultrasound image during prenatal (fetal) cardiac interventional procedures using real-time positional tracking of the ultrasound image plane via a magnetic field generator and sensor(s). Success with this system in aligning a needle to target (fetal aortic valve) along the preferred trajectory prior to entering the skin led to our decision to adapt this technology for use in central vascular access. We propose to develop a MNIO-VA solution using in vitro phantoms during this Phase I award to be followed by clinical trials in patients. Specific Aim 1. Adapt magnetic navigation (MN) and ultrasound image tracking solutions developed by our group for prenatal cardiac intervention (PCI) into a clinically intuitive line-of-sight image overlay (IO) solution to visualize the trajectories of needles to arteries and veins for rapid vascular access (VA). Specific Aim 2. Develop novel pulsatile vascular access phantoms that contain vessel pairs of varying diameters and depths and that simulate the 2D and color-Doppler characteristics of pulsatile arteries and veins for ultrasound-guided MNIO-VA training. Specific Aim 3. Test the speed and accuracy of a prototype MNIO-VA system using realistic, pulsatile arterial and venous vascular phantoms of varying vessel depths, diameters, and flow characteristics. General Relevance. Our proposed ultrasound-guided Magnetic Navigation, Image Overlay Vascular Access system will increase the speed, accuracy, and success of vascular access in infants and children and will reduce the complication rates associated with medical therapies that depend on central vascular access. Our proposed Magnetic Navigation, Image Overlay Vascular Access system will increase the speed, accuracy, and success of vascular access in infants and children and will both reduce the stress and increase the effectiveness of medical therapies that depend on central vascular access. [unreadable] [unreadable] [unreadable]